1. Field
One or more example embodiments relate to a power supplying apparatus used for a neural activity recorder, and more particularly, to a power supplying apparatus with an improved common-mode rejection ratio.
2. Description of Related Art
A neural activity recorder may be connected to a detection electrode provided for each of channels of the neural activity recorder, a reference electrode configured to provide a reference voltage to measure a voltage of the detection electrode, and a ground electrode configured to emit noise of the neural activity recorder. The detection electrode and the reference electrode may be connected to a low-noise amplifier (LNA) of the neural activity recorder, and the ground electrode may be connected to a ground of the neural activity recorder.
The neural activity recorder may collect neural signals such as an action potential and a local field potential using a potential difference between the detection electrode and the reference electrode. Herein, a plurality of detection electrodes whose number is equal to the number of the channels of the neural activity recorder may be provided, and a single ground electrode and a single reference electrode may be provided. The neural activity recorder may include a same number of LNAs as the number of the channels. A positive input terminal of each of the LNAs may be connected to each of the detection electrodes. The reference electrode may be connected to negative input terminals of all the LNAs.
Thus, an input impedance mismatch indicating that an impedance of a positive input terminal and an impedance of a negative input terminal of each of the LNAs differ from each other may occur. The impedance of the positive input terminal and the impedance of the negative input terminal may differ from each other, and thus a common-mode rejection ratio of the neural activity recorder may be reduced.